Changes

Remember you should have exported the RPI_ROOT enviroment variable previously.

On the raspberrypi host, SDL2 will be always used since it provides graphics acceleration.

''Note:'' If you are building ScummVM on your RPi itself, you might run out of memory during linking. If you use GNU ld for compiling you can try exporting LDFLAGS="-Wl,--no-keep-memory" before running configure. This tells GNU ld to optimize for memory usage.